^ not sound advice. If you have an old and weak system, that is all the more reason to switch to 8.1.

8.1 has a much lower impact on resources, so fits well with lower performance machines.

Honestly though, if you are spending most of your time coding, you need to look at what languages you are going to get into heavy, and what type of servers they would run on. If you are going to get into C#, and use .net framework, then go with 8.1. But if you are going to get into Ruby or Python that work better with Linux and BSD systems, get a Mac.